Lubricating composition



tented Aug. 13, 1940 UNITED STATES rc/l/r v Examircr LUBRICATINGCOMPOSITION Benjamin T. Brooks, New York, N. Y., assignor, by mesneassignments, to American Cyanamid Company, New York, N. Y., acorporation of Maine a air an: PATENT OFFICE No Drawing. ApplicationMarch 18, 1937,

Serial No. 131,628

2 Claims.

This invention relates to lubricating compositions and particularly tothe so-called extreme pressure lubricants.

The standard lubricants for heavy duty service, that is, in internalcombustion engines, are mostly hydrocarbon oils. These mineral oils whenproperly refined are very stable under heat but they are deficient inoiliness and in the strength of the oil film which is formed betweenmetal surfaces in bearings or at other points Where lubrication takesplace. Both factors of film strength and oiliness are of greatimportance in the lubrication of heavy duty bearings such as areencountered in modern internal combustion engines or in geartransmissions with high tooth pressures, for example hypoid gears.Insufiicient film strength will result in metal to metal contact evenwhen an adequate quantity of lubricant is supplied to the bearing andinsufficient oiliness will prevent retention of an oil film in thebearing when for any reason a lubricant supply becomes insufiicient.Both deficient oiliness and deficient film strength permit metal tometal contact which results in higher wear and also in the rapiddevelopment of heat. Modern high speed internal combustion enginesoperate at so close to the limit of bearing pressures and rubbing speedsthat it has been necessary to change the material used in the bearing,for example, to substitute certain bearing metals such as alloys.containing silver, cadmium and the like, for the standard babbittmetals.

Film strength and oiliness are probably due to molecular forces in theoil film, the molecules of which have the property of wetting oradhering to the metal surface." An oil film is retained tenaciously evenwhen the lubricant supply is interrupted for considerable periods oftime.

In the past, the problem was first attacked by the incorporation ofsmall amounts of fatty acids into the oil. These compounds did in factincrease the oiliness to some extent but they did not produce films ofhigh strength and corrosion and other difiiculties rendered their useundesirable. Certain esters such as tricresyl and triphenylphosphate andchlorinated esters of fatty acids With mono or dihydric alcohols havebeen proposed and have achieved some commercial success, notably in thecase of tricresylphosphate and chlorinated stearic acid esters. Thepresence of the acid radical even though combined in ester form wastherefore considered to be a desirable component group of suchcompounds.

According to the present invention, I have found that ketones obtainableby combining long chain fatty acids such as oleic, stearic, palmitlc andthe like, or by combining the mixtures of g acids obtained fromcottonseed oil, lard oil, stearine, fish oil and talloel, and the like,when blended with lubricating oils or greases increase the film strengthnotably and greatly increase the oiliness of the products. These ketonesare very stable under heat and are not corrosive to metals. 10

The higher molecular unsubstituted ketones have the advantage over othersubstances used to increase film strength and oiliness in that they donot contain any halogen and therefore cannot decompose to yieldhydrochloric acid.

While the halogen free ketones are very effective and possess theadvantage that they contain no constituents which form hydrochloricacid, higher film strengths maybe obtained when the products arechlorinated. It is thus possible in the chlorinated products of thepresent invention to obtain the advantages and increased film strengthwhich halogen containing compounds offer, without excessive danger fromcorrosion due to possible formation of hydrochloric acid in use. Whenunsaturated ketones, such as oleones, are chlorinated the chlorine addsto the double bonds and di and tetra chloroleones are produced. Suchchlorinated ketones are not as stable as the monochlorinated products.They can be transformed into highly stable compounds by heat orpreferably by treatment with suflicient caustic soda to remove onechlorine atom as hydrochloric acid, HCl, from the dichlor product or twochlorine atoms from the tetrachlor product. The partly dechlorinatedproducts in which the chlorine is adjacent to an unsaturated or olefingroup are highly stable and the advantage of the chlorinated product maybe obtained without corro... sion dangers. Mixtures containing ketonesof the order of 1% give sufiicient increase in film strength andoiliness. Larger amounts can, of course, be used, but the factor ofdiminishing returns soon. enters and the advantage obtained by addingvery large quantities of the ketones do not offset the increase in costfor, of course, the ketones are much more expensive than the lubricatingoil base itself.

The ketone of the present invention are usabl with lubricating oils andgreases of the mos varying characteristics. The improvement in filmstrength and particularly in oiliness will, however, in general, differwith different mineral oils. Thus, for example, with a mineral oil stockwhich has been refined by solvents to such an extent 55 that it has lostmost of its oiliness, the addition of the ketones of the presentinvention will make a much bigger difierence than in the case of amineral oil where the oiliness has not been so completely removed. Itshould also be understood that the varying purposes for which thelubricating composition is to be employed determine to a large extentthe particular ketone which is to be used. Thus, for example, in thegear lubricants for hypoid gears, the film strength is of the greatestimportance and since the temperature of operation is relatively low,danger of decomposition of halogen containing compounds with the settingfree of halogen acids is not a serious factor. Chlorinated ketones maybe used which, in general, show a higher film strength. On the otherhand, in the case of lubricating oil for internal combustion engines,where the operating temperatures are high and danger of decompositiongreater, it is sometimes preferable to use unhalogenated ketones of thepresent invention which possess high degrees of oiliness with lower filmstrengths.

Other uses may emphasize one or other of the characteristics and in eachcase the ketone having the best general characteristics for theparticular use should be chosen. It is an advantage of the presentinvention that a wide choice of ketones halogenated and unhalogenated isavailable. While the halogenated ketones possess substantially similarproperties, whether the halogen is fluorine, chlorine or bromine, thebromine compounds are much more expensive and for the most purposestherefore the chlorine compounds are preferable because of the largesaving in cost.

The invention will be described in greater detail in conjunction withthe following specific examples which are typical illustrations of usesof the compounds of the present invention.

Example 1 .1% of stearone was added to a standard mineral lubricatingoil for internal combustion engines and tested on the lubricant testerdeveloped by the Bureau of Standards with a high speed test specimen of2500 R. P. M. and low speed specimen of 938 R. P. M., giving a speedratio of 8:3. The rate of loading increased about 12 lbs. per second andthe initial oil temperature was 75 F. Under these conditions, themixture showed a load carrying capacity of 185 lbs. as compared to 148lbs. for the oil without ketone.

t marked increase in oiliness can be noted.

Example 2 Chlorinated stearone containing one atom of chlorine per molewas mixed with the same mineral oil as described in Example 1 andtested. A 1% solution gave a film strength of 185 under more drasticconditions, involving a speed ratio of 5:1 instead of 8:3. Thechlorinated compound, while giving very satisfactory film strengths,requires somewhat larger amounts. These larger amounts, however, confera higher degree of oiliness so that a 1% chlorinated stearone mixture insome respects is distinctly superior to a 1% of stearone solution.Chlorinated stearone is also more soluble in mineral oils than stearone.

Example 3 Chlorinated oleone and stearone were tested in a 1% solutionin a naphthenic base oil on a diflerent type of machine, namely, anAmsler machine which has a maximum reading of 300 lbs. Both mixturesshowed a maximum film strength at 300 lbs. at a torque of '75 lbs. forthe chlorinated oleone and 58 lbs. for the chlorinated stearone. TheAmsler machine not only measures film strength but gives a roughcomparison of oiliness. Tricresylphosphate which is a standard additionto lubricants to endow them with extreme pressure characteristics whenused in a 1% solution in the same naphthenic base oil as the chlorinatedstearone and oleone above referred to, gave a film strength of 160 lbs.with a torque of 68. When the amount of tricresylphosphate was increasedto 2% the film strength rose to 200 lbs. with an increase of torque to80. -It will be apparent that at a much higher loading the chlorinatedstearone gave a lower torque and hence was more oily than the 1%tricresylphosphate solution and the chlorinated oleone at a 50% higherload gave somewhat lower torque than the 2% tricresylphosphate solution.

It is an advantage of the present invention that the addition of thechlorinated ketones does not raise the pour point of the lubricant andmost of them lower the pour point, which is, of course, of greatadvantage as material savings in refining cost can be enjoyed if theadded compounds exert sufiicient lowering of pour point to make the lessrefined oil meet the normal requirements. Similarly the pour pointdepressing effect of the compounds of the present invention may be usedwith oils which already have a very low pour point due to very thoroughremoving of wax, thus producing products which have pour points lowerthan ordinarily specified which special oils can then be used forextreme cold weather operation.

I claim:

1. A lubricating composition comprising a mineral lubricant and a smallamount of stearone.

2. A lubricating composition comprising a mineral lubricant and a smallamount of chlorinated stearone.

BENJAMIN T. BROOKS.

